Re: [RESEND PATCH v7 1/1] PCI/sysfs: Expose PCIe device serial number

[Matthew Wood]

Thank you all for the helpful responses!

> Hello,
>
> > > I can see that the PCI r3.0 (conventional PCI) spec doesn't include
> > > the Device Serial Number Capability and the PCIe spec does include it,
> > > but this seems like it would fit better in the pci_dev_dev_attrs[],
> > > and the visibility check would be parallel to the
> > > dev_attr_boot_vga.attr check there.
> >
> > I'm not sure I agree. The pci_dev_dev_attrs apply to all pci devices,
> > but DSN only exists in PCIe Extended Capability space. Conventional pci
> > config requests couldn't even describe it, so seems okay to fence it off
> > using the PCI-Express attribute group that already has that visibility
> > barrier.
>
> PCI-X 2.0 added Extended Configuration Space[1].  Perhaps why Bjorn had
> different attributes group in mind here.

Looking more at pci_get_dsn, I see that there's no check for pci_is_pcie so I
understand the thoughts here and can see how it would make sense to move
to pci_dev_dev_attrs.

I also agree that the visibility check for dsn would match the
existing dev_attr_boot_vga
check, with the additional advantage of not making the existing attrs in
pcie_dev_attrs_are_visible oddballs without visibility checks.

I will prepare a v8 with that change, thanks again!